Feeding device for gyratory crushers



May 30, 1950 o. c. GRUENDER 2,509,920

FEEDING DEVICE FOR GYRATORY cRusHERs Filed Aug. 4, 1947 v sheets-sheet 1 May 30, 1950 Filed Aug, 4. 1947 O. C. GRUENDER FEEDING DEVICE FOR GYRATORY CRUSHERS 7 Sheets-Sheet 2 i?faewor scar C @riff/ml @MIM May 30, 1950 o. c. GRUENDl-:R

mums DEVICE FOR GYRATORY cRusHERs Filed Aug. 4, 1947 '7 Sheets-Sheet 4 May 30, 1950 o. c. GRUENDER FEEDING DEVICE FOR GYRATORY CRUSHERS' @Scar C 'fzzender Filed Aug. 4, 194WV May 30, 1950 o. c. GRUENDER FEEDING DEVICE Foa GYRATORY cRUsHERs- '7 Sheets-Sheet 61 Filed Aug- 4, 1947 May 30, 1950 o. c. GRur-:NDER 2,569,920

FEEDING DEVICE FOR GYRATORY cRusHERs AIlly/ .V/AWII lll Patented May 30, 1950 FEEDING DEVICE FOR GYRATORY CRUSHERS Oscar C. Gruender, Milwaukee, Wis., assignor to Nordberg Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Application August 4, 1947, Serial No. 766,044

3 Claims. l

My invention relates to an improvement in fine reduction or attrition mills.

One purpose is to provide an improved mill in which materiels may be reduced to substantial iineness.

Another purpose is to provide an improved mill in which hard materials, such as ores, can be reduced to extremely line sizes.

Another purpose is to provide an improved feeding means for gyratory Crushers and mills.

Another purpose is to provide an improved liquid seal for such mills.

Another purpose is to provide an improved main frame for such Crushers and mills.

Another purpose is to provide an improved attrition liner.

Another purpose is to provide improved locking means for the attrition liner.

Another purpose is to provide improved centering and bearing means for the actuating eccentric of sucll mill or crusher.

Another purpose is to provide improved means for preventing rotation of the bowl of such a mill or crusher in relation to the main frame.

Another purpose is to provide improved lubricating means for such mill or crusher.

Another purpose is to provide improved sealing means for the top of the head and eccentric of such mill or crusher.

Another purpose is to provide a pneumatic release for such mill or crusher.

Other purposes will appear from time to time in the course of the specication and claims.

I illustrate the invention more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is vertical axial section;

Figure 2 is a similar partial section on. an enlarged scale;

Figure 3 is a section on the line 3-3 of Figure 1;

Figure 4 is a section on the line 4-4 of Figure 2;

Figure 5 is a section, .on an enlarged scale, on the line 5-5 of Figure 4;

Figure 6 is a section on the line 6-6 of Figure 2;

Figure 7 is an enlarged detail of the structure shown in Figure 6 Figure 8 is a section on the line 8--8 of Figure 7;

Figure 9 is a section, on an enlarged scalejon the line 9 9 of Figure 7;

Figure 10 is an enlarged detail, in vertical radial section, of the liquid sealing portion of the device;

Figure 11 is an end elevation taken along the line II-II of Figure 3;

Figure 12 is a partial vertical axial section through an upper portion of the feed plate structure;

Figure 13 is a. detail of a sealing ring shown in Figure 12; and

Figure 14 is a section, on an enlarged scale. on the line III-I4 of Figure 13.

Like parts are indicated by like symbols throughout the specification and drawings.

Referring to the drawings, I generally indicates any suitable base upon which the Crusher or attrition mill is mounted. 2 generally indicates a, circumerentially extending main frame member having a top, outwardly extending, generally horizontal Ilange 3, and l is a bottom ange, the two anges connected and strengthened by the vertical ribs or webs 5. 6 is any suitable grouting on base I and upon which the main frame is positioned.

Mounted on, and removably secured to the upper edge of the main frame, and overlying the iiange 3, is a normally fixed abutment member or bowl supporting or receiving abutment ring 'I having a downwardly extending, circumferential outside flange 8 which surrounds and conforms to the edge of the ange 3. The ring has an inner, upwardly extending bowl abutment portion or bowl receiving flange 9, having a generally conic, outwardly tapered inner face I0, a nat top face II, and a generally cylindrical outer face I2. I3 indicates three suitable U-shaped arm elements or inwardly extending radial ribs connecting and supporting the central hub I4.

Mounted within the hub I4 is the preferably somewhat conic central post I5 which conforms to a similarly formed inner face I6 of a generally central aperture of the hub I4. The post I5 has a downwardly reduced lower end portion I'l, shown as screw-threaded as at I8. The post I5 has an upper and generally cylindrical portion I3, shown as provided with an exterior, circumferential oiling slot 2l), and a horizontal oil passage 20a, which may suitably communicate with an axial oil passage 2| connected to any suitable oil delivery duct 22 from a, suitable source of oil or lubricant.

23 is a nut. inwardly screw-threaded to receive the exterior threads I8 of the lower end of the shaft I5. It has vertical slots at the lower portion, as indicated at 24, and an upper, outwardly extending ange 25 in a supporting ring or securing member 26, removably secured to the lower end of the hub I4, as by any suitable securing bolts 2l. Dust entrance is prevented by any suitable packing 28. It will be understood that when it is desired to remove the post I5, nut 23 is rotated in the opposite direction, causing the under side of the flange 25 to bear against the supporting ring 26. This results in an upward thrust on the threads of the post I5, freeing it from contact with the surface I6 of the hub I4. By continuous rotation of the nut, the post I is raised until the threads are no longer in engagement, permitting upward removal of the post. It will be understood that when the post is in position, itis fixed, and that the outer and generally spherical surface of its upper portion I9 constitutes a central support for the later described crushing head and its actuating means.

Surrounding the post portion I9 is an eccentrically apertured sleeve 30, which constitutes a unitary actuating member for gyrating the below described crusher head and for rotating the below described feed plate 45. It may be supported at its lower end as by a bearing ring 3| held against rotation in relation to the sleeve 38, as by pins 32. It rests upon the normally fixed bearing ring 33, suitably held against rotation in relation to the upper end of the sleeve I4. 34 is a bevel gear which may be keyed to the eccentric sleeve 30, which meshes with a pinion 35 on the drive shaft 36 rotated by a suitable exterior pulley 31, shown as channeled as at 3B to receive V-belts or other suitable driving means. The gear has a circumferential vertical flange 34a located within the circumferential ring 34h, integral with the arms I3. In the event of shaft failure, the gear and eccentric will move only slightly laterally, because the flange 34a will prevent such lateral displacement. Any suitable bearing assembly may be employed for the shaft 36. I illustrate a surrounding sleeve 39 carrying suitable bearing units 40 and 4I at its opposite ends. 42 generally indicates any suitable sealing structure. The sleeve 39 is shown as having an exterior closure flange 43, with which it is integral, which fits in and closes an aperture surrounded by any suitable sleeve 4, forming part of the main frame circumferential wall 2. 45 is an oil supply passage, and 46 a suitable oil removal passage.

It will thus be clear that, in response to belts engaging the drive pulley 31, the eccentric sleeve 30 will be rotated about the upper central post portion I9. The eccentric sleeve 30 is shown as having an upwardly extending portion 50, the f upper end of which is shown in greater detail in Figure 12. Secured to it, as by screws 5I, is a feed plate 52 having a circumferentially extending, downwardly faced slot 53. As will he clear from Figure 12, this slot is desrcibed about a center, indicated at X, which is eccentric to the center Y, Iabout which the eccentric sleeve 30 rotates. The result of the rotation of the eccentric sleeve 38 is a rotation of the plate 52.

Any suitable top wear plate 54 may be secured to the plate 52, as shown in Figure 1, as by suitable screws 55. Thus material dropped upon the top of the feed plate 54 will be laterally, centrifugally thrown, as will later appear.

56 is any suitable bearing sleeve between the outer surface of the post I9 and the inner surface of the eccentric sleeve 30. It may be apertured as at 51 for the admission of oil, such aperture being aligned with the oil aperture 58 extending generally radially through the eccentric sleeve 30.

60 generally indicates a gyrated crushing head which is gyrated about the center, in Figures 1 and 2, at A. It includes an upwardly extending hollow stem portion 6 I, externally screw-threaded as at 62. 63 is a sealing ring bearing against the inner surface of the hollow stern 9i, but seated in a circumferential, outwardly opening slot 64 in the upper end portion 50 of the eccentric sleeve 30. It will be noted that the slot 64 is normal with the inclined axis X, and lies in a plane slightly inclined from the normal in relation to the center Y.

'I'he head 60 is provided with a. downwardly extending sleeve portion or bearing sleeve 85 m which surrounds the eccentric sleeve 30 and is separated from it by any suitable wear-taking sleeve or liner 61 with its oil-passing aperture 68 aligned with an oil passage 69 in the lower portion of the head 60. The head also includes any suitable connecting webs 10 and a spherical bearing portion 1 I, the exterior and generally spherical bearing surface of which rest upon any suitable upwardly concave bearing or spherically surfaced supporting ring 12 mounted on an intermediate portion or extension of the main frame 2, as shown in Fig. l, which surrounds, but is outwardly spaced from, the post portion I9. 13 isan annular oiling passage in the ring 12. Oil holes connect this passage with the annular oiling passage 13a, and oil holes 14 conduct the oil to the interior of the machine. It will be noted that the inner surface of the sleeve 65 is inclined in relation to the center Y, but is concentric with the center X. It will be understood that as the eccentric sleeve rotates, it imparts to the head 60 a gyratory movement about the center A.

15 indicates a crushing or attrition member or somewhat conic die or mantle resting upon an appropriately formed upper supporting surface 16 of the head 68. The die 15 is held in position by a generally conic positioning thrust member or sleeve 11 which is formed at its upper edge, as at 18, to receive a locking member or thrust ring or securing nut 19. The thrust ring or nut 19 is inwardly threaded, as at 80, to conform to the exterior threads 62 of the upper hollow stem portion 6I of the head 60. The ring or securing nut 19 is also provided with an upwardly extending seal-ing ring portion 8l which extends into the circumferential, downwardly opening annular channel or groove 53 in the lower surface of the plate 52. Suitable sealing rings or packings are provided, as at 83, 84 and 85, received in appropriate annular recesses, whereby the ring 8| is sealed at both sides. An upper sealing member or ring 86 is positioned in the slot 53 and is held against rotary movement, as by suitable positioning pins 81 extending into apertures 88 in the vupper part of the plate 52. The ring 86 is provided with an exterior sealing member 89,

which may be of rubber.

It will thus be understood that whereas the head may gyrate about the center A, in response to rotation of the eccentric sleeve 39,

leakage of oil from the inside to the outside is prevented, and also the inward penetration of dust particles from without. Nevertheless, the plate 52 and its outer wear-taking feed plate 54 may rotate in unison with rotation of the ec- 65 centric sleeve 30, whereas the head 60 and its wear-taking die 15, rotate only slightly, as they gyrate.

r The head 60 is provided with an outwardly extending portion 90 upon which the exterior 70 apron 9| may be secured. 92 indicates the downwardly and inwardly extending guard secured to the outer edge of the portion 96 of the head. Its lower edge 93 extends into a gutter 94 formed in the circumferentially extending annular portion 95 of the main frame. Asuitable liquid,

` suitable screws l` I 8.

such as water, is delivered to the gutter I4, for example, along any suitable duct I6. a constant circulation of water beingmaintained; The water tends to fill the gutter 94 and to flow thereabout, overflowing inwardly over the edge of the inner dam 91. This dam may be in the form of a circumferentially extending ring defining th space 98 from which one or more outlet passager. 99 may extend. Such passages are shown in Figures 1, 2 and 10, and are directly above the U-shaped arms I8.

In Figure 1 is indicated a closure plate |00 through which water may ow along any suitable discharge pipe As will be clear from Figure 10, I may provide any suitable splash-preventing elements. I illustrate, for example. a horizontal ring |02 extending outwardly intermediate the upper and lower edges of the dam 91. I illustrate, also, inwardly extending rings |03 and |04 inwardlyextending from the outer inclined wall |06 of the gutter 94. I illustrate a vertical ring |06, shown as generally cylindrical and as downwardly depending from a lower portion of the head extension 90. In addition, I illustrate the surrounding and preferably flexible packing ring |01, upwardly extending from the upper outer edge of the gutter 94 and held and protected by .a circumferentially extending metal ring ||0.

In order to cause a positive movement of the water along the bottom of the gutter 94 I provide the following structure. The water inlet passage 96 delivers water through a duct |15 to an annular passage ||6 located beneath the bottom of the gutter 94 and closed by a plate or plates secured in position, for example, by It will be noted that the screws enter the upper surface of a ledge H9, located at one side of the passage ||6, 'as shown in Figure 10. The water which is delivered to the passage IIB along the duct I| may escape through the plate or plates ||`I through one or more upwardly extending discharge passages |20. These passages are partly closed by deflector plates I2! spaced upwardly from the upper surface of the member ||1, as by spacers |22, which leave a free space |23, as shown in Figure 8. With water being delivered under pressure tothe pasinto the interior ofthe gutter 94, are therefore carried over the upper edge of the dam 91 and are removed along the passages 99 and the discharge ducts |0|. Note, as in Figure '7, that the outlet |23 may be somewhat outwardly flared, as at |23a.

As many of the discharge passages may be employed as is convenient or necessary, twelve being shown in Figure 6. Whereas the number may be varied to suit the needs of a particular situation, I find that a, structure with twelve of the delivery passages |23 and three cf the outlet passages 99 works efficiently. Thus, when the eccentric sleeve 30 is rotated, andthe feed plate 54 is rotated, and the die 15 is gyrated, there is no perceptible entry of dust into the necessary series of bearings. And oil may be delivered from any suitable source, along the oil inlet duct 22. and may flow through the above described oil ducts and such additional ducts as are shown at y |26, etc., back to the oil return pipe |26.

Opposed to the attrition die 15 is the upper attrition liner or ring |30. It will be noted that the opposed surfaces of the members 15 and |30 are generally conic, but converge somewhat toward the outlet or lower and outer end of the attrition zone defined between the two members. The bowl liner |30 is mounted on a tiltable or releasable bowl and support, which will now be described. The bowl structure proper, indicated at |3I, has a bottom web or portion |32 and a preferably integral outer cylindrical portion |33, exteriorly screw-threaded, as at |34, and having an upper annular portion |35 with a more or less conic inner surface |36 and an outwardly extending top flange |31. It is provided, also, with generally radial ribs |438 having upper edges which downwardly and inwardly prolong the conic surface |36, and which receive a Vconic feed hopper or feed directing ring |39, removably secured, as by members |40, to the surface |36, and overlying the upper inner edge of the bowl liner |30. It will be noted that the liner |30 has an upwardly extending annular portion |4| with an outwardly extending top flange |42 which may be apertured or provided with exteriorly open notches |42a.; Keys |43a are secured. to a. split or segmental threaded locking ring |43, the keys entering the exterior notches |42a. preventing rotation of the locking ring in relation to the member |30.

The ring |43, in turn, is externallyl screwthreaded, as at |44, to conform to interior threads |45 on the annular locking member |46 which seats in a recess or on a shelf |41 on au upwardly and Vinwardly extending bowl bottom portion |32a. The ring |46 has upwardly extending lugs |48 adapted to be received in notches |50 in segmental locking plates |43. The plates |49 have external notches |5I adapted to engage forward edges of the bowl. Thus, since the ribs |38 are fixed, the locking plates |49, when in the position in which they are shown in Figures 2 and 4, prevent any rotation of the ring |46. This, in turn, holds the bowl liner |30 upwardly drawn against the conic surface of the bowl portion |32a. How'- ever, when removal of the liner |30 is desired, it is a simple matter to lift the locking plate |49 upwardly out of locking position, and to knock the ring |46 to the released position, by operat- `ing a tool or hammer against the upwardly extending lugs |48. The deflector gutter |39, meanwhile, both protects the above described structure and directs the "feed downwardly and inwardly toward the attrition zone between the members 15 and |30.

Any suitable feed-directing or limiting means |60 may be employed, as shown in Figure 1. It may include, for example, an outer circumferential ring I6 l an inner and feed aperture defining ring |62, and suitable reinforcing or connecting members |63. The structure, as a whole', may rest upon the portion |35 of the bowl structure, being centered in any suitable shelf or circumferential ledge |64.

' The bowl structure proper is adjustably mounted in `a bowl support, generally indicated as |10. It includes a generally cylindrical inner portion |1|, inwardly screw-threaded, as at |12, to conform to the exterior threads |34 of the bowl wall |33. The bowl may be raised or lowered by a relative rotation of the portions |33 and |1|. When the adjustment has been made, the parts may be locked against relative rotation by the ylooking or thrust screws |134which1ms through'theilange |31, and' may be locked in position as by lock nuts |14. Any suitable packing or'dust guard means'may be employed, as

at |19 and |11. vThe outer dustyguard'l11 bears against thel inner surface of the cylindrical ring which may be welded" or otherwise secured to the exterior of the `bowl portion |31.

It willfbe understood that'any suitable means y |1| and |33. I illustrate, for example,'the wind-r 'lass |90` with its actuating handle |9| and its Aflexible element |82.- The details of this structure do not, o"f themselves, form part of the present invention, and will not be further described, it being understood that any suitable means may be employed forvimparting an adjusting rotation to the member |33 in relation to the member |1|. It will be'understood that the exterior of the member |1| is provided with a plurality of vertical recesses |1|1.f I may lock the parts against relative rotation byY a suitable removable locking block |93, shown in Figure 1 as removably secured to a lower portion of the ring |18, as by am! suitable locking screw, |94. The member |93 has an inwardly extending lug |85 adapted to enter one of the slots or Vchannels |1|a.

The portion |1| has an outwardly extending bottom flange |90 with a plurality oi lateral arcuate edged bosses or enlargements l9| apertured. as at |92, to receive tension rods, which will later be described, but which permit the ring support structure to tilt upwardly away from the flange 9. against which it normally seats, when tramp iron or uncrushable material is present in the crushing or attrition zone. In order to prevent rotationof the bowl support and to insure that the parts seat or are centered properly when the bowl support drops back into the normal position in which it is shown in Figure 1, I provide a plurality of lugs |93, outwardly extending from some of the bosses |9| and carrying an arcuate surfaced abutment` |94 which may be the head of a removable screw or bolt |95, held in position, for example, by a nut/|96, as shown in Figure 11. The arcuate or domed surface of the member |94 abuts against a positioning pin |91, suitably hardened, which is removably positioned on the flange 1. It may, for example, pass through a boss 1a, and have a reduced shank |90, the lower end of which is screw-threaded, as at |99, to receive any suitable securing nut 200.

The bowl support |1| may normally be held in the position in which it is shown in Figure 1, by any suitable releasable means. I illustrate, for

' example, the tension rods 205 which pass through the apertures |92 and have enlarged upper holding heads 206, downwardly domed as at 201, to engage seating pockets 208 which surround the upper ends of the apertures |92 through the bosses |9|. These pockets perform a centering "function, as is shown in Figure l, whereby the member 205 is kept out of contact with the walls of the apertures |92, with a consequent prevention of wear.

The flanges 3 and 1 are apertured, as shown at 209 and 2|0, to clear'the member or rod 205. The rods extend downwardly through suitable apertures 2|| in any suitable yoke or yokes 2|2, normally held in downward position by thrust pistons 2|3 in suitable cylinders 2|4 secured to the lower surface of the main frame flange 3. It will be understood that a suitable liquid or fluid, under proper pressure, is delivered to the interior of the Vpiston structure so formed, in

such fashionv that the downward thrust against the member or members2|2 normally exceeds the crushing or attrition stress. But when al Y predetermined crushing or attrition stress is exceeded, or when uncrushable material passes through the crushing zone .defined between lthe members and |30, thenthe bowl structure can -The details of the pressure maintaining means are not herein shown, since they do not, of themselves, form part of the present inventionr and are shown and described in my earlier filed, copending application Serial No. 697,227, Pneumatic release vfor cone crushers, filed in the United States Patent Office on September 16, f

It will be realized that, whereas, Ihave described and illustrated a practical and operative device, nevertheless many changes may be madfl in the size, shape, number and disposition of parts without departing 'from vthe spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustratlve or diagrammatic, rather than as limiting me to my precise showing.

The use and operation of the invention areas follows: I

I illustrate an attrition or reduction mill in i which a gyrated head gyrates about a predetermined center A within a normally fixed bowl.

rI he head carries an attrition die 15, and the bowl carries an attrition liner |30. Thematerial to be reduced passes through the fixed feed limiting ring |52 in the plate |50. Any suitable feed limiting means or feeders may be employed. The material to be ground,A in suitable volume, is delivered to the upper surface of the rotating plate 54. The rotation of the plate projects the material centrifugally outwardly against the feeding hopper |39, resulting in a substantially uniform feed throughout the periphery of the crushing or attrition zone. The particles are delivered downwardly and inwardly by the hopper |39, and are received by the member 11, the surface of which is generally perpendicular to the path of downward and inward movement of the particles. The particles there received are substantially stopped, and then ilow downwardly and outwardly into the attrition zone between the opposed surfaces of the members 15 and |30. The gyration of the die 15 about the center A lifts the material upwardly, as it flows outwardly through the attrition zone, and grinds it against the liner |30. Since the individual particles are substantially smaller than the distance of closest approach between the opposed liner and die, the mass of particles are ground upon and against each other. die 15 prevents an unduly rapid passage of the particles through the attrition zone. They receive a number of impact and attrition impulses, which varies with the particular machine, but which is preferably not less than five or six. The reduced particles thereafter escape over the lower, outer edge of the die 15, pass over the apron 9|, and 'escape downwardly through the discharge space |'a in the base It will be understood that 78 the arm structure i3 and the sleeve surrounding The relatively slight angle of theV in connection with a gyrated head, properly lends itself to use with fine, intermediate, and coarse gyratory Crushers. The same is true of the waterseal above described.

In considering the general application or operation of the various features above described, I employ a normally fixed central post |9 about which the ,eccentric sleeve 30 rotates. The eccentric sleeve performs the double function of gyrating the head 60 and of rotating the feed plate 54. The material passing through the attrition or crushing zone is reduced by the lgyratory movement of the head 60, the material being actually engaged by the die 15 and the liner |30. The water seal is advantageous in that water is caused torotate in the trough or gutter 94. The various outwardly extending flanges or rings, as shown in Figures 2 and 10, prevent splashing of the water and escape of the water outwardly over the edge of the trough or gutter 94. The rotation of the water in the gutter or trough causes it to adhere to the walls. and this surface tension lessens the tendency of the water to partake of the gyratory movement of the member 92 or of any part associated with the head itself.

The sealing ring 86. shown as expandlble in Figures 13 and 14, located in the top plate 52, is preferably formed in halves, and rotates with the feed plate support 52, through the medium of the pins 81. A rubber ring or washer 89 is fitted into an exterior recess in the ring halves 98. When the ring halvesy 86 rotate, with the feed plate support 52, centrifugal force urges each half outwardly, causing it to urge the rubber ring or washer 89 against the outer wall of the slot 53 of the feed plate support 52. Thus the ring does not bear heavily against the contacting face of the head nut or its upward extension 8|. The rubber ring 89 further effects a perfect seal against the entrance of dust at the outer diameter of the ring. And since the ring 86 bears against the top of the head nut, no dust can enter underneath the ring. The ring halves 86 may be made of a lead-base bronze and no lubrication is reouired. No matter what wear takes place to change the vertical position of the ring 8E in respect to the contacting parts, it will automatically find its new position, and function effectively to seal the top of the machine against the entrance of dust.

The above described means for holding the die 15 in place are of the self-tightening type. The nut 19 is threaded to engage the exterior threads 82 on the head, and bears against the intermediate members 11, which contact and thrust downwardly and outwardly against the die 15, holding it constantly firmly in position. The upper attrition member or liner |30 is also of the self-tightening type, because the threaded locking ring |43 is forced to rotate with it.

The rapidly revolving feed plate is an essential element of my attrition mill, and without lt. it would be impossible to get a uniform mixture 10 of coarse and ne material all around the crushing or attrition chamber. The primary :function of the feed spout or aperture |82 is to direct the material to the center of the feed plate.v It may also be employed for feed limitation.

Throughout the description of the structure herein I` have spoken of my invention as a crusher or attrition mill. earlier pointed out, many of the features may be applied to crushers. But a primary purpose of my invention is to provide an attrition mill to produce a much finer product than is normally produced by so-called Crushers, even by what are called in the eld"flne crushe'rs. MY attrition mill is not, as such, a crusher. and is not properly described as a crusher. I shall now desclilbe the use of my invention as an attrition m I produce fines by attrition, and not by the crushing of a single layer of particles between crushing members. Material of minus 1/2 inch, inch, or 41 inch, containing fines, is fed to the mill. The material is delivered by the spout or delivery ring |62 upon the center of the rapidly rotating feed plate 54, and centrifugal force mixes the material and feeds it in a uniform stream to the stationary conic hopper |39. This centrifugal feeding action delivers athorougli'ly mixed feed all around the attrition chamber, no matter how much segregation may have occurred by the time the material is landed on the feeding plate. The material enters the attrition chamber between the attrition members 15 and |30 in a thick stream. 'Ihe lower member 15 may be considered a die, and partakes of a gyratory movement, about the center A, of an amplitude somewhat greater at the discharge periphery than at the point of entrance. For instance, in a. 4-foot mill the movement at the feed entrance or inner edge of the member 15 may be of the order of 11,/2 inch, while the movement at the discharge edge is of the order of 2 inches. The angle of the attrition member 15 is less than the angle of repose of thel material undergoing attrition. If the lower attrition member had no movement, the material would remain stationary on it, the movement of the head providing the means whereby the material is progressively propelled through the attrition chamber.

The material entering the attrition chamber on its open or inner and upper side is compacted, by the propelling stroke of the head, until the mass is reduced to approximately one-half its initial thickness. Since the particles are superposed on each other, the initial impact is most effective in making a large amount of fines. The coarse particles in the feed serve as commuting media, much as balls function in a conventional grinding mill. Hence, the importance, both of using a mixed feed, and of uniformly distributing the coarser particles in the mass. This result is obtained by the centrifugal action of the revolving feed plate 54.

After the lower attrition member 15 has reached its closest approachto the upper attrition member or liner |30, the speed and amplitude of retration are such that the mass falls generally vertically, under gravity, away from the upper attrition member to a lower position on the lower or gyrated attrition member. This results from the fact that the length of movement of the head, and its speed of movement, are such that it is withdrawn from lbeneath the crushed or compacted material faster than the material will accelerate under gravity. The mass I have done this because, as

isstill `when the lower yattrition llhas reached its point of furthest recession from f the upper attritionmember |30.

As the lower attrition member reverses its dil rection of movement'and again rises to'ward the upper member, it strikesthe freely fallingmass,

and eifects a. separation of the particles. As

it completesits upward movement of closest approachto the upper member, itv again impactsl and compresses the mass against the upper attrition member. This cycle of free fall and sube.

tain a fair percentage of coarse particles, to provide voids in the mass and to preventpacking. My principle of attrition reduction, of alternately impacting and releasing a thick mass of material, so that the mass moves progressively through the attrition chamber, produces a large amount of nes. About 30% to 40% of the discharged product may be minus ,65 mesh. which is ideal for flotation in` the non-ferrous metal field. The. minus 65 lmesh particles may be extracted by screens, classifiers, or by pneumatic separation. The oversize product is advantageously fed back to the attrition mill, in closed circuit. My process of attrition reduction does not require a close setting of the attrition members. The members are set relatively far apart, to provide space for the mass, but this coarse setting produces a 11ne-l sized product.

As to the structure of the mill itself, I employ an improved main frame which can advantageously be used in connection with gyratory crushers. The same is true of my improved main shaft or central post structure. y

Y ing surface ecentrically offset in relation to the inner surface of the sleeve, the axes of its inner and outer surfaces being inclined, and intersecting at a point above the top of said fixed post, said eccentric sleeve having `an upward projection and a generally horizontal feed plate mounted thereon, a driving connection for rotating said After bei-susanne tstherfa;

positioned adjacent the top of the crushing orv attrition zone, a hopper formed and adapted to' deliver material directly into the vupper portion of the attrition zone throughout its circumferthe crushing or attrition zone, including a rotat-V f ence, centrifugal means in said hopper for mixingl material and` for distributing the material, toy

able feed receiving member mounted for rotary movement in the hopper about the vertical axis of the mil1,1means for delivering feed to said' rotary feed member, and driving means for rotateccentric sleeve and feed plate, a head including a bearing lsleeve surrounding and conforming to the exterior surface of said eccentric sleeve, a support for said head, positioned outwardly of said post, said head and said support havingr opposed conforming spherical bearing surfaces concentric with the point of intersection of the axes of the inner and outer surfaces of the eccentric sleeve, and-a sealing Aconnection between said head and said feed plate. f

2. In a crusher or attrition mill, an upper and, normally fixed material engaging member, a lower material engaging member. the two meming the feed member at a suillcient rate of rota'- tion, to impart substantial centrifugal movement to articles fed thereto, whereby said feed member is adapted to distribute materia) throughout the circumference of the hopper, said driving means including a driving connection with said gyrating means. f Y.

3. The structure of claim 2 characterized by and including a ilxed post, having an outer bearing surface, an eccentrically apertured sleeve rotatable about said bearing surface, and means REFERENCES CITED The following references are of record in the file of this patent: f

UNITED S'IIATES PATENTS Number Name l Date 243,545' Gates June 28, 1881 271,138 Bharpneck Jan. 23, 1883 768,955 Russell Aug. 30, 1904'` 1,145,629 Symons July 8, 1915 1,226,275 Symons May 15, 1917 1,402,255 Sanborn Jan. 3, 1922 1,537,584 Symons May 12, 1925 1,553,202 Symons Sept. 8, 1925 1,791,584 Symons Feb.,.10, 1931 1,817,044 Symons Aug. 4, 1931 1,863,529 Symons June 14, 1932 2,017,108 Symons Oct. l5, 1935 2,054,326 Jacobson Sept. 15, 1938 2,091,315 Gruender Aug. 31, 1937 2,135,324 Brown Nov. 1, 1938 2,147,833 Fahrenwald Feb. 21, 1939 2,254,425,j Fahrenwald Sept. 2, 1941 2,305,616 Gruender Dec.'22, 1942 2,306,437 Gruender Dec. 29, 1942 2,310,737 Gruender Feb. 9, 1943 2,341,543 Gruender Feb. 15, 1944 2,350,737 Elben L. June 6, 1944 2,359,987 Gruender Oct. 10, 1944 2,409,391 Rumpel Oct. 15, 1945 4 FOREIGN PATENTS Number Country Date 850,650 France Sept. 18, 1939 656,857 Germany Peb. 17, 1938 Y l ly 1 ,ing or attrition zone, gyrating means for, impart# ing to the lower material engaging member a" 

